// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_RENDERER_MEDIA_REMOTE_MEDIA_STREAM_IMPL_H_
#define CONTENT_RENDERER_MEDIA_REMOTE_MEDIA_STREAM_IMPL_H_

#include <memory>

#include "base/compiler_specific.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/single_thread_task_runner.h"
#include "base/threading/thread_checker.h"
#include "content/common/content_export.h"
#include "third_party/WebKit/public/platform/WebMediaStream.h"
#include "third_party/webrtc/api/mediastreaminterface.h"

namespace content {

class RemoteAudioTrackAdapter;
class RemoteVideoTrackAdapter;

// RemoteMediaStreamImpl serves as a container and glue between remote webrtc
// MediaStreams and WebKit MediaStreams. For each remote MediaStream received
// on a PeerConnection a RemoteMediaStreamImpl instance is created and
// owned by RtcPeerConnection.
class CONTENT_EXPORT RemoteMediaStreamImpl {
public:
    RemoteMediaStreamImpl(
        const scoped_refptr<base::SingleThreadTaskRunner>& main_thread,
        webrtc::MediaStreamInterface* webrtc_stream);
    ~RemoteMediaStreamImpl();

    const blink::WebMediaStream& webkit_stream() { return webkit_stream_; }
    const scoped_refptr<webrtc::MediaStreamInterface>& webrtc_stream()
    {
        return observer_->stream();
    }

private:
    typedef std::vector<scoped_refptr<RemoteAudioTrackAdapter>>
        RemoteAudioTrackAdapters;
    typedef std::vector<scoped_refptr<RemoteVideoTrackAdapter>>
        RemoteVideoTrackAdapters;

    void InitializeOnMainThread(const std::string& label);

    class Observer
        : NON_EXPORTED_BASE(public webrtc::ObserverInterface),
          public base::RefCountedThreadSafe<Observer> {
    public:
        Observer(const base::WeakPtr<RemoteMediaStreamImpl>& media_stream,
            const scoped_refptr<base::SingleThreadTaskRunner>& main_thread,
            webrtc::MediaStreamInterface* webrtc_stream);

        const scoped_refptr<webrtc::MediaStreamInterface>& stream() const
        {
            return webrtc_stream_;
        }

        const scoped_refptr<base::SingleThreadTaskRunner>& main_thread() const
        {
            return main_thread_;
        }

        void InitializeOnMainThread(const std::string& label);

        // Uninitializes the observer, unregisteres from receiving notifications
        // and releases the webrtc stream.
        // Note: Must be called from the main thread before releasing the main
        // reference.
        void Unregister();

    private:
        friend class base::RefCountedThreadSafe<Observer>;
        ~Observer() override;

        // webrtc::ObserverInterface implementation.
        void OnChanged() override;

        void OnChangedOnMainThread(
            std::unique_ptr<RemoteAudioTrackAdapters> audio_tracks,
            std::unique_ptr<RemoteVideoTrackAdapters> video_tracks);

        base::WeakPtr<RemoteMediaStreamImpl> media_stream_;
        const scoped_refptr<base::SingleThreadTaskRunner> main_thread_;
        scoped_refptr<webrtc::MediaStreamInterface> webrtc_stream_;
    };

    void OnChanged(std::unique_ptr<RemoteAudioTrackAdapters> audio_tracks,
        std::unique_ptr<RemoteVideoTrackAdapters> video_tracks);

    const scoped_refptr<base::SingleThreadTaskRunner> signaling_thread_;
    scoped_refptr<Observer> observer_;

    RemoteVideoTrackAdapters video_track_observers_;
    RemoteAudioTrackAdapters audio_track_observers_;
    blink::WebMediaStream webkit_stream_;

    base::WeakPtrFactory<RemoteMediaStreamImpl> weak_factory_;

    DISALLOW_COPY_AND_ASSIGN(RemoteMediaStreamImpl);
};

} // namespace content

#endif // CONTENT_RENDERER_MEDIA_REMOTE_MEDIA_STREAM_IMPL_H_
